Biochips are very high performance analysis tools in fields relating to molecular biology. The technology for preparing them is in the process of becoming established. Their use will enable research to be accelerated and will lead, in particular, to new diagnostic techniques.
A biochip is a set of systems of biological recognition substances such as biological molecules, all operating in parallel. Amongst biochips, those which have been developed to the greatest extent so far are DNA chips and there are great hopes that they will enable recognition efforts to be greatly increase in the field of molecular genetics.
Physically, biochips are structures constituted by a solid support having distinct zones distributed thereon, in general of microscopic dimensions, and supporting identical biological recognition probe substances, each zone or site having a single type of substance which may be of biological or biochemical origin. Recognition is performed by a specific affinity interaction between the probe substance fixed on the support and the target substance contained in the solution to be analyzed. The biochip is read by marking the target substance using a marker, generally a fluorescent marker. During recognition, the target substance brings its marker to the zone that supports the probe substance. Knowing the nature of the probe makes it possible to know the target substance with which the affinity reaction has taken place.